renaming and refactoring

renaming and refactoring

Changed the names of many functions and macros to get rid of the
symbols with "js" in them--its not Javascript, it's Parenscript!  Most
of those symbols were renamed with "script" replacing "js".

Also changed the main compilation interfaces to use the function
COMPILE-SCRIPT and the macro SCRIPT from JS-COMPILE and JS
respectively.

Additionally, the first steps of the package system are included (with
the addition of a the SCRIPT-PACKAGE and COMPILATION-ENVIRONMENT
classes).  These are integrated into the current compiler, though they
probably break a few "traditional" serialization methods, specifically
because macro and special form names are stored as symbols rather than
strings and EQL comparisons are used rather than STRING-EQUAL
comparisons of the strings.

I have also split parser.lisp into parser.lisp and macrology.lisp.
Parser.lisp contains mechanisms for parsing Parenscript given an input
s-expression while macrology.lisp contains language definitions that
make use of the parsing mechanisms.

All tests now pass, though the documentation has gone slightly out of
date with the symbol renaming.  This will be fixed shortly.  More
tests and functionality need to be added to make the current
Parenscript compatable with the older semantics (as dicussed,
comparing macro/special form names based on their string values is the
main thing).